#include <bits/stdc++.h>
#define int long long
using namespace std;
const int N = 200010;
const int mod = 998244353;
vector<int> f[N];
signed main() {
    cin.tie(0)->sync_with_stdio(false);
    int n, c, w;
    cin >> n >> c >> w;
    const int inf = 2e18;
    for (int i = 1; i < N; ++i) f[i].resize(N / i + 2, inf);
    f[1][1] = c;
    for (int i = 1; i < N; ++i)
        for (int j = i + i; j < N; j += i) {
            f[i][j / i] = min(f[i][j / i], f[i][1] + w * (j / i - 1));
            f[j][1] = min(f[j][1], f[i][j / i] + c);
        }
    int mx = inf;
    for (int i = 1; i < N; ++i)
        for (int j = 1; j < f[i].size(); ++j)
            if (i * j >= n) mx = min(mx, f[i][j]);
    cout << mx << '\n';
    return 0;
}